This IS the Avid L2: Re: [Avid-L2] 23.98 vs 24

Monday, June 22, 2015

Re: [Avid-L2] 23.98 vs 24

Could someone clarify the terms "Pull Up" and "Pull Down" as it related to field sound recording? I had originally thought that when shooting a true 24 fps knowing it would be posted at 23.976 the field recorder would be set to sample at 48.048 Khz. This would then be played back at 48.000K to slow down, pull down, the sound to match the video that would be slowed down to 23.976.

On the other hand shooting 23.976 for a true 24 delivery the sound recorder would run at 47.952 KHz. Then this would again be run at 48.000 KHz to speed up, pull up, the sound to match the true 24 fps playback.

Do I have this correct? I've started to hear about field recorders that are recording at 48K but restamping the files with a different sample rate to accomplish pull down or pull up. I'm just not clear if in the field the recorder is actually altering it's sample rate or is it the flag for the sample rate? Any other insight would be appreciated.

---In avid-l2@yahoogroups.com, <cutandcover@...> wrote :

I agree. And if you have a problem with sound drift, the freely available Wave Agent can batch re-stamp sample rates into WAV files. I've had to do this from time to time when production rolled sound with pull-up for no reason other than it had been set by the last person who'd rented the sound recorder.

On Mon, Jun 22, 2015 at 2:48 AM, 'Edit B' bouke@... [Avid-L2] <Avid-L2@yahoogroups.com> wrote:

Ok, first, I don't want to argue with a DP, nor with Jay, but my ideas:

Having to use the shutter to fix a discrepancy between frequencies may result in a (relative) short shutter time,

and that will of course have impact on the motion blur and the amount of light that is needed.

But, modern ballasts are high freqency, there is no flicker issue anymore in pro lighting.

On the other hand, i fail to see the problems when posting at 24.

With the recent thread about 8.3 being able to playback any rate frame by frame, the only issue with 24 could be a sound speed mismatch.

And that is a very easy fix.

(But even that 'should' not happen.)

Bouke

VideoToolShed
van Oldenbarneveltstraat 33
6512 AS NIJMEGEN, the Netherlands
+31 24 3553311

----- Original Message -----

From: David Dodson davidadodson@... [Avid-L2]

To: Avid-L2@yahoogroups.com ; oliverpetersvidy

Sent: Sunday, June 21, 2015 11:01 PM

Subject: Re: [Avid-L2] 23.98 vs 24

Well, this is an Oscar-nominated DP, so he knows what's what. He's talking about flicker as it relates to on-set source lighting and HMI's being shot in Kyiv, Ukraine. The difference in power standards can be problematic sometimes.

David Dodson

davidadodson@...

On Jun 21, 2015, at 1:57 PM, oliverpeters@... [Avid-L2] <Avid-L2@yahoogroups.com> wrote:

Why does the DP think he'll have flicker issues? Has he ever shot anything else at 23.98 or 24.0 digitally? If so, was there flicker?

I've never found this to be an issue with proper professional lighting; however, I have seen flicker when consumer lighting is in the shot - regardless of frame-rate

I concur with the other comments - you are really throwing a monkey wrench into dailies delivery, sound post, color grading, screening of cuts on video, etc. But yes, it can be done. You also won't be able to easily integrate other cameras like DSLRs and GoPros where sync sound is involved and there's a mix of cameras. That's because these cameras generally do not have a 24.0 mode.

- Oliver

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